Driving mechanism



Aug. 15, 1950 P. K. BEEMER ETAL DRIVING MECHANISM Apg. 15, 1950 Y P. K. BEEMER Erm. 2,519,170

DRIVING MECHANISM Filed May 7, 194e 4 sheets-sheet 2 Bni-'y 7.17.1 ahr :Paul .Klleamer Eiff- MWL/@gz Aug. 15, 1950 P. K. BEEME r-:r AL

DRIV-ING MECHANISM 4 Sheets-Sheet 3 Aug. 15, 1950 P. K. BEEMER ETAL 2,519,170

' lDRIVING MECHANISM 'Filed May 7, 194s 4 sheets-sheet 4 v /fa N l TF 7.11 K Eeemez" fig-5:

a supporting plate 25. (See Fig. 9 for the details of this mounting.) Plug 24 is rotatably ad- ;iustable in plate 25 and is secured to the plate and set in any adjusted position by the studs or bolts 26 shown in Fig. 2. The inner end of plug 24 is slotted at 21 to receive one end of a torsion spring 28 'which lies within hollow shaft 29 and whose otherend (see Figs. l and 4) is held in a slotted plug 29 fixed in shaft 2|] in any suitable manner as by a bolt or rivet 30. By proper adjustment and setting of plug 24, which is equipped with wrench sockets 3| for Vthe purpose, flat spring 28 is put under an initial torsional strain which tends to rotate shaft and the parts attached thereto inthe direction indicated by the arrows in the several views, counter-clockwise as viewed in the aspects of Figs.2, 3 and 5. The plug may then be secured in its set position by the bolts 26. To accommodate the rotational adjustment of the plug either it or plate may be provided with slotted openings or a series of bolt holes. These are not shown in the drawings, the illustration being based on the supposition that bolt holes are drilled through plate 25 in the positions which suit the adjusted position of the plug.

' The torsion spring 28 is specically shown in the drawings inthe form of a flat bar with its ends connected with plug 24 and shaft 28 by the simple expedient of being confined in slots. That is a preferled'form of the spring arrangement. But the spring bar may be of other crosssectional shapes, may be composed of ,two or more bars which together Vform a laminated bar, and may be attached at its ends in other manners.

' The driving shaft 46 (see'particularly Fig. 7) is mounted in bearings in a tubular shaft carrier 4|. As here illustrated, the preferred arrangement for Amountingshaft 48 in the carrier 4| is as follows. The Shaft is directlycarried by two ball bearings 42, the outer races of which are snugly fitted into annular adapters`43 which have inwardly turned annular flanges 44'at their inner ends and outwardly turned annular flanges 45 at their outer ends. A fairly soft annular rubber bushing 46 fits directly into each end of tubular carrier 4i, the bushing having an outwardly turned flange 41 at its outer end resting against the end of tubular carrier 4|. One of the cylindric faces of rubber bushing 46 is corrugated or toothed, preferablythe inner surface as shown at 48 in Fig. 10.

The described structure is highly advantageous for inexpensive and quick assembly ofthe parts. The metal adapter 43, which may be made of pressed sheet metal,v` tsnthe outer race of the ball bearing tightly and gives the bearing a good annular seat on the rubber bushing 46. With the metal bushing 43 inserted into rubber bushing 46, the whole assembly including the bearing, and the metal and rubber bushings, is then easily force-fitted into tube 4|, the toothed formation at 48 allowing an easy compressibility of the rubber bushing. And with the rubber bushing so constructed, the ball bearings, although securely held in place in Atube 4|, are allowed sulcient easy freedom for axial alinement with each other although the ends of tube 4| may not have been either machined at all or machined to any great accuracy.

Driving shaft is driven at its inner end (its end closer to the car center) from the running gear of the car; from some element which rotates with the wheel and axle unit, and'prefer- 4 ably directly from a car wheel, such as the car wheel illustrated at 5U. Driving from the car wheel, the drive is preferably through a traction roller 49 which normally engages the tread of 5 the wheel.

Fig. 7 shows one preferred form of such a traction roller and Fig. 8 a modified form. In Fig. 7 a flanged hub 5I is mounted on the inner end of shaft 40 and the members which make up the body of the traction roller are bolted to the flange of hub 5|. The main body of the roller includes a pressed sheet metal member 52 having an inwardly extending ange 53 which is bolted against the Iiange of hub 5|. The body 52 hasV a substantially cylindric portion 54 and a frusto-conical portion 55 at that end of cylindric portion V54 which faces inwardly in a direction away from the inner end of driving shaft 4|). The pressed sheet metal body is covered with a tread of suitable material, for instance, Vulcanized rubber. The traction tire indicated generally by the numeral 56 has a generally cylindric tread portion 51 and a frusto-conical tread portion 58.

In the form of traction. roller shown in Fig. 7V the frusto-conical portion 58 is extended by the conical surface 59 of a metal cone 60, theV taper of the cone being substantially the same as the taper of the conical tread surface 58. Bolts 6| serve to bolt both the cone 60 and the flange53 of the main roller body to the flanged hub 5|.

Immediately inward of the traction roller a fixed guard member 65 is xedly mounted on tube 4|. This guard member may be most conveniently formed by a piece of strap steel bent to the U-conformation yshown in Fig. 5 and welded at its ends at 66 to tube 4|. The guard lies close to the larger or outer end of the traction roller, and its rounded part which projects furthest from the axis of shaft 40 lies somewhat radially 40' inwardly of the outer cylindric tread surface 51 of the traction roller. The approximate relationship is shown in Figs. 5 and 7. The functions of this guard member, and the modified form 65a shown in Fig. l1, will be explained later when the action of the roller on the car wheel is explained.

Shaft carrier tube 4| and shaft 40 are supported on mounting shaft 20 in such a manner that 4B and 4| are movable as a whole in a generally vertical direction, specifically in this particular structure about the transversely extending axis of mounting shaft 28, and also in such a manner that each end of drive shaft 40 is allowed similar movement independently. The mounting shown in Figs. l to 6 comprises a single radial arm .10 rigidly mounted on mounting shaft 20 and carrying tube 4l so that it and drive shaft 48 have a swivelling movement about the axis of arm 10. In a preferred form such as shown in Fig. 5-arm 1|) is made up of an external tube 1| attached to mounting shaft 2D by welding as shown at 12. Within tube 1| asma-ller tube 12 ts movably, and a cross pin 13 set in outer tube 1| passes through slots 14 in the wall of tube 12 to prevent relative longitudinal movement of the tube but to allow a sufficient amount of relative rotation. The outer end of inner tube 12 has the carrier tube 4I rigidly mounted on it, as by welding as at 15."

Tube 4| and driving shaft'48'are supported in 70 such a position that the tread face 51 of thetraction roller is normally in 'about the central plane of the car wheel tread as shown in Fig. 1, and a belt sheave v|30 on the other or outer end of drive shaft 40' is in the plane'of sheave |4 on accessory 'driving shaft I3. A driving belt 8|l encircles the weer@ `here prefer'ejply 'embodied lnthe erm struture thenUeenstr/inediy eliows.ndeenderitiswinging .Y

fi.-eesmit einer;abouifeefmdi1-p'oih@e he .einegerteyzjeii-l directions or ini ya@ plegegW-hieh v:is determined by them-,1e of mvmentfzoffthemeeiel emr-iet point yelnctloy-` thefaXs-.nf the carrier ,and its driving shaft." l A VEtigli .ghoyye certainmodieeteneinfetrueture, @meng other things v rsifioigvngfthe;present feature of time `enelesed torsensprngeeppl-iedtua meuntng. shaft Which-1 carries'the driving `"siiafftmaur-ier threghetwoffarmsffasin ftheffprevieusfanlm f A-swill be l envious-fthe Aouter fendsef ishesmwspring gages lug 91M andthe -hatt lea'r Timun-the peint 11n me carrier iene-th!ideeerminewbyffme shown in Fig'. 1. On movementfo- -heiqalfiwhel the maximum movement of the wheel towardV the right. The guard thus prevents the traction roller from dropping any great distance below the flange periphery;'and upon return of the car wheel toward the 'left afshort frusto-conical face 51a on tread@ face 51 will climb the iiange. The pro- Vision of the guards makes it unnecessary to have another frelativelylong conical surface at the right hand side of the Ytraction roller like that at the left..v The amount by which the tracition roller drops after it has passed overk the wheel flange is determinedby the difference beztween the radius of roller tread 51 and the'maxll'num radiusof guard 65; and that difference :needonly Ybe enough to prevent the guard from contacting .the wheel tread when the roller tread 251 Yis normally riding the wheel-tread, allowing ifor a reasonableamount of wear reduction of the diameter of tread l. Y

The actionk of the traction roller has been described on -Vthe assumption that slots 'I4 in swivel tube l2 are suiciently long to allow swivelling movement ofv shaft carrier 4i to the extents described. VThe slots 'i4 may however be so positioned and dimensioned as to limit the downward swinging of the .roller end of 4| so that the extension coneEE may not be needed as the roller will. not drop belowy theposition in which the frusto-conical surface 58 will engage the edge of the car Wheel tread to climb it. FigiV 8 shows a modication in the form and make-up of the traction roller in which a cylindric metal extension member 5ta is substituted forV theV cone 5d of Fig. 7. Otherwise the structure shown in Fig. 8 is the same as that shownin Figf andthe same numerals are applied. The cylindric vdiameterk of 60a is substantially the same as the minimum diameter of rusto-conical tread face 58, and 6ta clears the .wheel Aflangevwhen tread 5i is riding the wheel tread,. The action of such a roller in following .the car wheel is the same as that previously described except that, when the car wheel moves relatively `toward the left in Fig. l the cylindric extension vSila continues to ride the car wheel :tread after conical face'Eii has left it and pre'- vents the traction roller from dropping below a point where conical face 58 will climb the tread @when the car wheel subsequently moves toward -,the right in Figi.. i A

,Figs. 1l ,and l2 also show a modified traction froller structure and a modified form of guard, ,either of which may be used with the mechanisms pfiFig. 1. The traction roller 4gb as there shown ,issimilar to that of Fig. 7, the same numerals being applied to similar or duplicate parts. rThe 4sheet metal body Mb of this roller is similar to Ibody 54 ofA Fig., '7 except that its conical portion ,55h 'is not faced by a conical rubber tread, the conical end face of the peripheral rubber tread '51h lying ush `with the metallic conical face which is mainly or substantially wholly the coni- .cal :face 59D ofthe metallic extension cone 69h. ,That extensioncone is here affixed (e. g. by welding) at its base directly to the frusto-conical por- ',tion 55hV of the main body, that truste-conical portion being recessed as shown so as to make I conical facetb flush with the narrow annular :frusta-conical surface 55o of the main roller body. iIhis4 unitary roller structure Yis mounted on the "langed hub 5i by bolting the body flange 53 to the Lhub. Y Figs.V Vl1 and l2 also show a modified form '.of 'guard'55a, similar to guard 65 of Figs. 5 and '7 except that its flange contacting face 65h is tilted at a slight angle to the axis of the driving shaft and roller. The direction of tilt is such that the guard edge which'lies adjacent the edge surface 51o of the roller tread is further from the shaft axis than is the opposite guard edge. That sloping guardface (see Fig. 1l) is in a position where in effect it forms an outward continuation of the somewhat concaved conical tread surface 51e, and thus acts to lift the roller and to feed the conical face 51e onto the car wheel flange as the flange moves toward the roller from the right in Fig. l1.V v

In drivingdevices of the character here described for driving any car accessory, and particularly for driving an air impeller in a refrigerator car, it is desirable to provide means for disconnecting the driving connection, either so that the accessory will not be operated while the car is in motion, or so that an auxiliary drive may be applied to the accessory when the car is standing. For instance, an auxiliary driving motor may be applied directly to accessory shaft I3 through the fitting I5 by applying a belt sheave to the screwthreaded hub |5115 and by then belting an auxiliaryy drive motor to that sheave. This, for instance, is done for pre-cooling operation of the air impeller before a refrigerator car starts its transit, or during stops to keep up the air circulation and refrigeration. In any such case it is necessary to disconnect the driving mechanism either at the traction roller or at the belt drive 8|, or at both. In the particular instance here shown the effective disconnection is made at both points. For that purpose an arm 90 (see Fig. 3) has at one end a strap or hub 9| which loosely encircles the outer end of mounting shaft 20. In its normal inoperative position the arm 90 rests on a supporting lug 92 which projects inwardly from the mounting plate 25. Mounting shaft 20 has a short radially projecting arm 93 which carries a lug 94' normally located above the normal position of arm 9E), as shown in full lines in Fig. 3, the clearance of the lug from' the arm allowing for all normal operative rotations of mounting shaft 20. When arm 9|] is raised to such a position as shown in dotted lines in Figs. 2 and 3 and hung up on an upper supporting lug 95. the 'armv comes into contact with lug 94 to rotate mounting shaft 20 in a direction to raise the radial swivel arm 10 and thus to raise the drive shaft carrier 4| as a whole. This general upward movement of the drive shaft carrier will tend to raise the traction roller off the car wheel and to raise sheave 80. To make certain however that sheave 8U is raised so as to relieve the normal tension on belt 8| so that the belt is not subjected to running wear when the auxiliary drive is applied, arm 9|) in moving upwardly also moves upv under the outer end of shaft carrier 4| to move that end of the shaft carrier, and sheave 8D with it, to such a position as is indicated in dotted lines in Fig. v3. 'Io make certain that belt 8| moves up and lifts off the upper sheave |4 a guard may be provided to move up under the belt. Such a. guard may be mounted either on handle 90 or on carrier tube 4|. It is here shown, at 96, mounted on tube 4|. The belt, being rather stii and conned by the wall surfaces of chamber ||b within the lcar wall structure (see Fig. 2) will lift at its upper end ofi sheave I4.

The mounting plate 25 hereinbefore referred to may be 'extended to'form the inner wall of a casing whichy encloses sheave and the lower part of drive belt 8| to protect them. For purposes vof easy'assembly the plate has an open- 1 #mismo also :largeeneirgh .tofaceommoate thee-relative movementsni ithe sheawe end @of the Idrive :shaft The lmoteotivefoasing as `also-in- -oludes .ibottom tand .aside walls .4M :and eouter wall Sl U2. f Ihercasingrmay., howevrerfhonsist -tirelyfof, these named walls., omitting,- .the .inner mail 4which ,here @shawn as vented by mounting, fplate ,2 5v.. ihercasing, :and the mounting fplate- 25 are hung, rior .instance .foy melding, ,'romfa structuhaimember fl whichfenmsi-a maat .for theabrieatediside sill ,of checar` tisdygnpen- .ings M4 and L05 'heixrgfoutmfthatesidessilistnuo- -iiuredio rpassfthefdttesbelti i.. TheLdr-ifving bett and sheaves, thus :substantially :completely enclosed within the ear :sill anomali structure rwitlnn the :lower foasingaareradeguately 3pm- ?Welaim:

. L .Imafcaristrnetureghauing rarhorly and a irelatively 2mm/,able ,gear a Wheel endxlereleme'nt; arising meohenismfior anae- -cessory "whiohiis caminav ,by the ear body and which haszanactuatingishaft; 'said driving anethaanism inc1udn.xa,driving shaft, fa shaft :carrier which the driviingsshaft tispiaurnalled, mount- .ing means fior ithefshattearrier ion. the roar boel-y supporting `#thematr-tier at afsingle point inten ,mediate the fendsiof theidriningshatt; thefmonnting means oonstrainedly I:allowing mouvement fof .said Amedialmeint .substantially y:along la lineiof 'moviemant to :and Afrom the wheel tand axle. ele- @ment aand the accessionsI shaft and (constrained-ly .allowing swinging movement of the carrier and .driving -shattt-substantiailgy Fin. a @lane whichy is oeter-minecl hy ssaidlinenrmovement and @the axis of said shaft, :and twogpower itransmitting means one between one endrof the-drivingshait and Ithe -wiheel-A Land axle f element and ithe other between the .other end 1nil-said shatt and -the ,ao- .oessery shaft, lloothipwer transmitting means the .fing rendered eiectiviefhyimovementsotheshat tends infsaid piane.v l

:adhv-ning mechanismias `:rieiined iin claim 1,

fand .-in which ithefrstfmentionedmower 'transmit-ting ,means includes ia traction holler adapted .to -tractiyely engage the roar wheel, .and ltheisecondfmentioned mower transmitting means .in- .cludes a .-sheave (and Joelt `-tr\ansxnission.

:3. .Drivingsmeehanism as defined in solaim 1, and in `svhichfthe ,mountingfymeans rior the shatt `cartier comprises aa motatalolyuneunted :mounting shaft, fa radial mem mounted :on the ,shaft said arm including .a component v.whichiis rotatable aboutthe longitudinalaxisof the Var-.n1 :and which .carries lthershatt carrierfatiitsiouter fend;v 4.y Drivingimechnnismfasrdenedinielaim .1, lamd in which the mountingmeansor xthe shafztcarrierzoomprises .a :rotatably mounted mounting sha-it., afradalanmcmounted on the shaft, said arm including a component which is rotatable about the longtudinalvamis sof Tthe'farm and which carriesthe shaft carrier at .its louter' lend; and a torsion spring housed within the mounting shaft and tending to rotate 'it and the arm in one direction Vabout the mounting shaft axis.

5. Driving mechanism ,fas defined in claim "l, .and inwhich the mounting-means for rthe'zshaft earnerc ornpri-ses` a `mountingplate carried by thrcerfbodaarotatebly adjustable plugtmormted y.on fand prareting through the plate, zafhollow mounting .shaft having one end' journalled on thefpkug, a car-bodyksupponted hearing .fior ithe other end of the mounting shaft, a torsion spring secured to that shaftsand the .other to said gplug, amd :a radial arm mounted on the mounting :shaft-andai;1 its `outer end supporting the driving shaft carrier, `said varm embodying a .swivel .allowing relative .rotary movement .of `the shaft carrier about the ylongitudinal axis'of :the arm.

f6'. nIn a `.driving mechanism of the .character described,` a .driving .shaft and .a shait carrier :on which the .driving shaft is carried, means for sllfriportingr the .shaft ,carrier `on a .car lhody .so .that y.one end of .the shaft lis .movable .to and from a car wheel .with the axisof the shat substantially .narallel 'to the normally positioned axis Lof. .the car wheel, a traction `roller on said .end ,of the driving shaft, .a fixed lguard merriher mounted on the .shaft .carrier .adjacent one .end nf the roller ,and 4adapted to engage and .ride the periphery ,of the oar wheel when that wheel InCA/iesavvay ,from 'the roller in anaxia'l 4direction in the .movements of 'the car wheel relative 'to 'the .car nod-y l.on which thes'haft carrierlismonnted, the ,traction roller lhaving .a substantially .cy- 'lindrc Wheel-engaging trealand having `a convcal tread r.extension at its end opposite -the end .adjacent `the ,guard merriher.v

11n a driving Amechanism .of 'the yc'hai-actor described, `a driving shatand a shaft. .carrier .on wlhich V thedriving shaft is carried, means ,for supporting the .shaft carrier onba ,car .body so that .one end of the Shaft movable .to .and Virorna car wheel with .the .axis .of the .sh-ait substantially ,parallel to ,the normally positioned axis of the car wheel., .a traction .roller onsad end Yof the ,driving.shaftL andaixecliguard member lmounted .on the vshaft carrier adjacent .one vend of the roller ,and adapted to engage and ride 'the periphery of the car wheel when that wheel moves away from the 4roller in .an eaxial .direction in 'the movements oi the `car wheel relative .to ,the carhody on whichthashatcarr'er is mounted, said ,auardhaving a .wheel engaging face which, iies `at an angle ltof the .axis .0I the shaft and roller, the edge of saidliacewhichiies adjacent 'the rol1er.`be'ing .urther removed ,rom vtheax'is than the ,opposite guard edge.v

8. In ,a ,driving mechanism of the character described, a .driving `sha'it and a .shatt carrier on, which ,the driving shaft 'is carriedmeansgfor supporting theV shaft carrier on. `a 4car body ,so lthat .one end oi the shaft 'is ,movable 1th .and from a `ear wheelwith the .axis of the shaft substantially parallel to jthe normally positioned axis vof fthe car .wheeh a traction roller on said `end of the driuzing shaft.. and axedrguarl memmnunted .on the shaft .carrier adjacent `Vone end offthe `roller and adapted to engage and ride theperiphery of "the car wheel when that wheel moves awayfrom the 'roller in anaXal direction :in the movements of the car wheel .relative to 'the .car'bodynn which .the shait .carrier V-S murted. Saidadi acent .Zend .of therollerhavug a frusta-conical wheelensaang periphery. Vthe guard having 4a wheelerigaging face whichlies at an angle to theaxis .o 'the shaft land roller, the edge ojf said face which lies 'adjacent xthe frustaconical race .of fthe roller having a .radius-hom said Aaxis `about equal to the .smaller .radius of `the rrusto-conical race, and the ,opposite .edge of .the guard having a smaller ,radius from said axis. l A,

9. In a .driving mechanism of the :character described, akdr'ivling .shaft and a .shaftiearrier on .which the .driving `shaft iscarried, means rior supporting fthe shaft .carrier onaaicar :body Tso housed within the mounting shaft with one end that one end ofthe shaft is movable to and from vsprings set in torsional tension.

10. In a driving mechanism of the character described, a driving shaft and a shaft carrier on which the driving shaft is carried, means for supporting the shaft carrier on a car body so that one end of the shaft is movable to and from a wheel and axle element of the car with the axis of the shaft substantially parallel to the normally positioned axis of the car wheel,

a traction roller on said end of the driving shaft, said supporting means comprising a mounting plate carried by the car body, a settable plug mounted on and projecting through the plate, a

Ahollow mounting shaft having one end journalled on the plug and on which mounting shaft the shaft carrier is supported, a car-body supported bearing for the other Yend of the mounting shaft, a torsion spring housed within the mounting shaft with one end secured to that shaft, the other end of the torsion spring engaging with the settable plug so that the spring may be set in torsion by setting of the plug.

11. In acar structure having a body and a relatively movable running gear including a wheel and axle element; driving mechanism for an accessory which is carried by the car body and which has an actuating shaft; said driving mechanism including, a mounting shaft rotatably mounted on the car body, a driving shaft, a shaft carrier on which the driving shaft is journalled, means for supporting the shaft carrier, at a point intermediate the two ends of the driving shaft, on the mounting shaft, said means comprising exclusively a single supporting arm vrigidly mounted on the mounting shaft and extending radially therefrom and supporting the shaft carrier at its outer end in such manner that the shaft carrier and driving shaft swing with the arm about the axis of the mounting shaft and are allowed exclusively swinging movement with relation to the mounting shaft and the single supporting arm in a plane which is substantially parallel to the axis of the mounting shaft and which is substantially normal to the radial extent of the supporting arm, two power transmitting means one between one end of the driving shaft and the wheel and axle element and the other between the other end of the driving shaft and the accessory'v shaft, both power transmitting means being rendered effective by movements of the shaft ends in said plane, and a spring having one end anchored on the car body and the other end applied directly to the mounting shaft to apply rotational torque to it and thereby tending` to swing Ythe medial supported point of the driving shaft in one direction about the axisrof the mounting shaft.

12. In a car structure having a body and a relatively movable running gear including a wheel and axle element; driving mechanism for an accessory which is carried by the car body and which has an actuating shaft; said driving mechanism including, a hollow mounting shaft rotatably mounted on'the carv body, a driving shaft, a shaft carrier on which the driving shaft isjournalled, means for supporting the shaft carrier, at a point intermediate the two ends of the driving shaft, on the mounting shaft, vsaid means comprising av vsupporting arm rigidly mounted on the mounting shaft and extending radially therefrom and supporting the shaft carrier at itsV outer end in such manner that the shaft carrier and driving shaft swing with the arm about the axis of the mounting shaft and are allowed 'swingingmovement in a plane which is substantially parallel to the axis of the mounting shaft and which is substantially normal to the radial extent of the supporting arm, two power transmitting means one between one end of the driving shaft and the wheel and axle element and the other between the other end of the driving shaft and the accessory shaft, both power transmitting means being rendered effective by movements ofthe shaft ends in said plane, and a torsion spring located within the hollow mounting shaftand having one end anchored on the car body and the other end applied tc the mounting shaft toapplyrotation'al ytorque to it and thereby tending to swing lthe medial supported point of the driving shaft in one direction about the axis of the mounting shaft.

V13. Driving mechanism as defined in claim 12 and in which the means for supporting the shaft carrier comprises also another radially extending arm mounted to swing about the axis of the mounting shaft independently of the rotation of that shaft and supporting the driving shaft carrier near one end of the driving shaft, said arm embodying a swivel allowing relative swinging movement of the shaft carrier about the longitudinal axis of 'the arm.`

14. In a driving mechanism of the character described, a driving shaft and a shaft carrier on which thedrivi'ng shaft is carried, means for supporting the shaft carrier on a car body so that one end of the shaft is movable to and. from a wheel and 'axle element of the car with the axis ofthe shaft substantially parallel to the normally positioned axis of the car wheel, a power transmitting element on said end of the driving shaft, said element being rendered effective and ineffective-by said movement of the shaft with relation to the wheel and axle element, said supporting means embodying a hollow mounting shaft journalled on the car body and upon whichthe shaft carrier is mounted, a torsion spring lying within the hollow mounting shaft with=oneend of the spring connected to said shaft, and-means for connecting the other end of the shaft tothe car body with the torsion spring set in torsional tension.

- PAUL K. BEEMER. HENRY O. FUCHS.

REFERENCES CITED v The following references are of record in the le of this patent:

" OConnor Aug. 4 5, 1947 

